package org.andromda.android.utils;

import java.io.Serializable;
import java.io.Writer;

/**
 * {@link Writer} implementation that outputs to a {@link StringBuilder}.
 * <p>
 * <strong>NOTE:</strong> This implementation, as an alternative to
 * <code>java.io.StringWriter</code>, provides an <i>un-synchronized</i> (i.e.
 * for use in a single thread) implementation for better performance. For safe
 * usage with multiple {@link Thread}s then <code>java.io.StringWriter</code>
 * should be used.
 * 
 * @version $Revision: 1003647 $ $Date: 2010-10-01 21:53:59 +0100 (Fri, 01 Oct
 *          2010) $
 * @since Commons IO 2.0
 */
public class StringBuilderWriter extends Writer implements Serializable {

	/**
	 * 
	 */
	private static final long serialVersionUID = 6770199056551025782L;
	private final StringBuilder builder;

	/**
	 * Construct a new {@link StringBuilder} instance with default capacity.
	 */
	public StringBuilderWriter() {
		this.builder = new StringBuilder();
	}

	/**
	 * Construct a new {@link StringBuilder} instance with the specified
	 * capacity.
	 * 
	 * @param capacity
	 *            The initial capacity of the underlying {@link StringBuilder}
	 */
	public StringBuilderWriter(final int capacity) {
		this.builder = new StringBuilder(capacity);
	}

	/**
	 * Construct a new instance with the specified {@link StringBuilder}.
	 * 
	 * @param builder
	 *            The String builder
	 */
	public StringBuilderWriter(final StringBuilder builder) {
		this.builder = (builder != null ? builder : new StringBuilder());
	}

	/**
	 * Append a single character to this Writer.
	 * 
	 * @param value
	 *            The character to append
	 * @return This writer instance
	 */
	@Override
	public Writer append(final char value) {
		this.builder.append(value);
		return this;
	}

	/**
	 * Append a character sequence to this Writer.
	 * 
	 * @param value
	 *            The character to append
	 * @return This writer instance
	 */
	@Override
	public Writer append(final CharSequence value) {
		this.builder.append(value);
		return this;
	}

	/**
	 * Append a portion of a character sequence to the {@link StringBuilder}.
	 * 
	 * @param value
	 *            The character to append
	 * @param start
	 *            The index of the first character
	 * @param end
	 *            The index of the last character + 1
	 * @return This writer instance
	 */
	@Override
	public Writer append(final CharSequence value, final int start,
			final int end) {
		this.builder.append(value, start, end);
		return this;
	}

	/**
	 * Closing this writer has no effect.
	 */
	@Override
	public void close() {
	}

	/**
	 * Flushing this writer has no effect.
	 */
	@Override
	public void flush() {
	}

	/**
	 * Return the underlying builder.
	 * 
	 * @return The underlying builder
	 */
	public StringBuilder getBuilder() {
		return this.builder;
	}

	/**
	 * Returns {@link StringBuilder#toString()}.
	 * 
	 * @return The contents of the String builder.
	 */
	@Override
	public String toString() {
		return this.builder.toString();
	}

	/**
	 * Write a portion of a character array to the {@link StringBuilder}.
	 * 
	 * @param value
	 *            The value to write
	 * @param offset
	 *            The index of the first character
	 * @param length
	 *            The number of characters to write
	 */
	@Override
	public void write(final char[] value, final int offset, final int length) {
		if (value != null) {
			this.builder.append(value, offset, length);
		}
	}

	/**
	 * Write a String to the {@link StringBuilder}.
	 * 
	 * @param value
	 *            The value to write
	 */
	@Override
	public void write(final String value) {
		if (value != null) {
			this.builder.append(value);
		}
	}
}
